Quick easy question. Wood's catalog states "...any high compression engines should use at least 3.37 ratio or higher."

Doing a bobber build, and getting ready to buy primary and sprockets. Few open primary belt drive options out there gearing wise so it will come down to the rear chain drive sprockets to achieve what is needed

When they say "higher" does that mean numerically as in greater than 3.37, or less than 3.37. I have been reading to try and find out this answer and I'm getting a bit confused. I know how to do the basic calc by dividing each individually and then multiplying primary and rear drive. Thanks in advance

 

What bike, year and motor and trans...? It all can make a difference.....

 

Thank you for the reply, but cam and all that was not the question. I know all that plays a part in the engine build as a whole, not the focus of my question. Just wanted some clarity on the ratio numbers game that is all.

So back to the original question, I am confused when Woods says recommend to have a 3.37 ratio or better.....does better than 3.37 mean higher numerically or lower numerically when you calculate your gear ratio. I am getting mixed up in my searching.

 

I only misspelled the word "can". I wasn't talking about cams.

Anyways, a 3.37:1 is probably the highest you want to go on the street. I think Bob was referring to the difference between a stock configuration as compared to a higher gear. Yes higher number. The higher from what ever you currently have the better.

 

Yes, a higher number.

 

You should take account of the complete quote in the Woods catalogue!

"For best overall performance we recommend using a Andrews 30 tooth transmission pulley on any bike with any type camshaft! W-9 or W-9B cams & any high compression engines should use at least 3.37 ratio or higher."

....which answers your question. In other words lower your overall gearing, by using a higher number!

 

I have a different view and see final drive gearing as being completely unrelated to the motor configuration but related to the how the motorcycle will be ridden. Obviously, if the bike is a bar hopper and the owner is most interested in light to light quickness and less interested in the higher cruise rpms, a 3.37 final drive would be better than 3.15. However, on the other hand, if the bike will be used to tour and the owner is interested in comfort and fuel economy, the opposite would be true. IMHO, the more torque the motor develops, the more inclined one might be to run the taller final drive gearing. Honestly, I don't see any reason to run a final drive higher than 3.37, i.e., say 3.50, particularly if the transmission is a six speed when one can use the first five to get point to point quick but upshift to 6th gear when cruising. But that's JMHO......

 

I have to agree with you djl. that's why I set my gearing to a 3.27:1. It gives me 5th at 2700@60 mph and 6th at 2750@70 mph. I set to what I like to cruise at.....

 

Agree. I made a minor mistake of lowering the gearing at the same time I did a major motor build. No way did I need 3.37 gearing. Not a big deal but an unnecessary expense. Cam choice is relevant to gearing as well.